1. Field of the Invention
The present invention relates to heating devices, and in particular, relates to heat pump heating devices which utilize stored thermal energy within the earth.
2. Description of the Prior Art
The prior art includes a number of references which teach the use of a heat pump to recover thermal energy stored in the earth.
U.S. Pat. No. 3,965,694 (Vignal) discloses an apparatususable either for heating or cooling which includes a compressor for compressing a refrigerant. A first heat exchanger transfers heat between the refrigerant and the atmosphere, while a second subterranean heat exchanger transfers heat between the earth and the refrigerant. A capillary tube restricting device is positioned in the refrigerant line between the first and second heat exchangers to liquify the refrigerant before it reaches the subterranean heat exchanger.
U.S. Pat. No. 2,513,373 (Sporn) discloses a heat pump system for either heating or cooling water or air. This system utilizes a closed circuit refrigerant line. A closed circuit water line circulates water through a pair of subterranenan heat exchangers. A heat exchanger which is coupled to both the closed circuit refrigerant line and the closed circuit water line transfers heat energy between the independent water and refrigerant systems. Depending on the operating mode of the system, heat is either transferred from the earth to the refrigerant or from the refrigerant to the earth.
U.S. Pat. No. 2,529,154 (Hammond) discloses a solar heating system. Water is circulated within a closed system coupled to a solar energy heat absorber. The refrigerant is circulated through a second closed system. A heat exchanger is provided to transfer heat from the water system to the refrigerant system.
U.S. Pat. No. 3,392,541 (Nusbaum) discloses an air conditioning/heating system having a plurality of compressors and heat exchangers.